GURPS Dinosaurs Pseudo-Conversions: Charismatic Cretaceous Carnivores

The long overdue second post of GURPS Dinosaurs Pseudo-Conversions covers some of the more famous active hunters of the Cretaceous period that have become frequent stars in written and filmed media. This monstrous menagerie is made up of seven theropod dinosaurs, as well as one awe-inspiring crocodilian. As with any GURPS Dinosaurs Pseudo-Conversions post, refer to theintroductory postfor some basic conversion logic being used, as well as for mental lenses such as using PK’s house rules separating Will and Perception from IQ.

This 25′ to 30′ long theropod from Argentina takes the biological features of its family, the abelisaurids, to their logical extreme: slender legs, thick tail, relatively long neck, thick skull with rugose cranial ridges, big shoulders, and almost vestigial arms. Its snub nose and brow horns give it a unique facial profile put on the big screen in films such as Disney’s Dinosaur and the upcoming Jurassic World: Fallen Kingdom (both of which have a bulkier, more heavy-legged creature than the fossil material indicates). The morphology of its Carnotaurus‘ tail suggests it had thick, meaty tail muscles that would have been a great stabilizer during fast runs but also stiffen the connection between it and the hips, preventing it from being used to steer particularly well when turning. Conversely, its clawless and impotent vestigial hands would have had no capabilities whatsoever, with the weight of hunting and inter-species conflict being entirely placed on its long, muscular neck and vicious hatchet jaws.

At the time of the writing of GURPS Dinosaurs, the bone beds which yielded Carnotaurus were believed to be from somewhere in the early Cenomanian (~100-95 MYA), the first age of the Late Cretaceous, which would have placed it alongside famous Argentine giants such as Argentinosaurus and Giganotosaurus; further studies and better understanding of the formation in question in the over two decades since have instead revealed it to be from the early part of the Maastrichtian (~70 MYA), living alongside later dinosaurs from the country such as Austroraptor, Noasaurus, Dreadnoughtus, and Saltasaurus.

Variant, Abelisaurus [-10 Points]: The namesake of the abelisaurid family, Abelisaurus lived around 80 MYA in Argentina. It was around the same general size as Carnotaurus, but with a bulkier frame, longer snout, and no brow horns. Increase ST to +26 [12], and remove both Horns [-2] and Enhanced Move [-20].

Variant, Smaller Abelisaurs [+2 Points]: A number of slightly smaller abelisaurs around 20′ in length are mechanically similar enough to Carnotaurus to be lumped in as a stat block variant, including India’s Indosuchus and Rajasaurus, Madagascar’s Majungasaurus, and Argentina’s Aucasaurus and Skorpiovenator. Change Size Modifier to +3, reduce ST to +18 [14] and Enhanced Move to Ground Move 9 [-10], and remove Horns [-2].

Arguably one of the most important catalysts of the Dinosaur Renaissance, Deinonychus stalked across the western United States around 115 to 108 MYA; incomplete fossils from Maryland may represent the genus, which would give it a presence on both sides of the Niobrara Seaway. It measured 11′ in length from snout to tail, and would have stood waist-height to an average human. The formidable arsenal of this predator included sharp teeth and curved talons on both the hands and feet, as well as the eponymous “terrible claw”, a large sickle-like claw on the second toe of each foot. Unlike the swift, scaly, problem-solving pack hunter of the movies, the real Deinonychus was an almost certainly feathered animal whose leg bones indicate a compromise between speed and strength

The most likely method of attack seems to be raptor prey restraint (RPR), wherein the animal would have pounced on prey before clenching its feet in a grapple on the unfortunate meal, making lacerating bites – and possibly kicks with a free foot if the prey was small enough – to rip off pieces of flesh that were consumed as the prey was still in the process of dying; RPR is replicated above by techniques, with the course of action being Attack From Above, followed by Targeted Attack, and finished with a combination of Stamp Kick and regular bite attacks. . There is possible evidence that Deinonychus may have hunted in packs to take down larger prey, but some have argued that the evidence instead points toward Komodo dragon-like mobbing (disorganized group hunting driven by opportunity) or multiple lone Deinonychus coming in to feed and dying to the same trap.

Deinosuchus was an immense alligatoroid crocodilian that ranged across much of North America from around 80 to 73 MYA; some claims have been made that the genus survived until the very end of the Cretaceous, but Deinosuchus expert David R. Schwimmer has contested such claims as being based on material that is more likely to belong to the giant gharial-like crocodilian Thoracosaurus. Based on fossil locations, Deinosuchus was mostly a coastal stalker of brackish water channels and beachfront that would occasionally veer into freshwater swamps, similar to the modern saltwater crocodile. Prey species could have included the giant coelacanth Megalocoelacanthus dobiei, the side-necked turtle Bothremys, trionychid (softshell) turtle species, primitive sea turtles that had arisen near the beginning of the Late Cretaceous, hadrosaurid dinosaurs, and various scavenging opportunities. Deinosuchus had jaws and teeth that would have been well-suited for sheer crushing force, backed up by Campanian turtle shells with large tooth holes bored into them by their massive pressure.

There are two currently accepted species of Deinosuchus, one from each side of the vast Niobrara Seaway that once divided North America into the two continents of Laramidia and Appalachia. In the eastern continent of Appalachia was Deinosuchus rugosus, which maxed out at around 26′, while Laramidia was home to the imposing 40′ long Deinosuchus riograndensis. The statistics above are for D. riograndensis.

Variant, Deinosuchus rugosus [-20 Points]: The eastern variety of Deinosuchus has a smaller maximum length than its Larimidian counterpart. Change SM to +4 and ST to +34 [-20].

After being described in 1995, Giganotosaurus quickly rose to a brief stardom in the “bigger than T. rex” fervor that has hounded popular perceptions of many theropods. While individuals were as long as or longer than Tyrannosaurus at around 40′ to 43′ in length, its more slender allosaur-like frame would have likely rendered it somewhat lighter than the barrel-chested girth of Tyrannosaurus. This giant theropod lived in the verdant floodplains that spread over Argentina around 100 to 97 MYA. Unlike the crushing bite force of the tyrannosaurids, Giganotosaurus and kin had jaws adapted for speed over strength, and likely used a technique known as ‘worrying’ wherein rapid slashing bites are employed to leave profusely bleeding wounds that eventually down the prey animal; this is reflected mechanically by the Targeted Attack in the template stat block. A geologically younger relative of Giganotosaurus known as Mapusaurus was discovered in a bonebed featuring multiple individuals of different ages, but as with most theropod bonebeds it is debated whether this is evidence of an organized pack structure or simple mobbing.

These stats can also be used for the similarly-sized carcharodontosaurids Acrocanthosaurus (western United States, around 116 to 110 MYA), Tyrannotitan (Argentina, around 112 MYA), Carcharodontosaurus (Egypt, Morocco, and Niger, around 112 to 95 MYA), and Mapusaurus (Argentina, around 97 to 94 MYA).

Spinosaurus, a denizen of the coastal mangrove swamps of Egypt (and possibly Morocco) around 97 MYA, is a dinosaur of eternal makeovers. Its first fossils were found in 1912 and named in a paper three years later. Portions of sail, lower jaw, and scattered bits such as strangely crocodile-like teeth were tantalizing, but ultimately doomed, as they were destroyed in the bombing of Munich during World War II. For a long period of time afterwards, including during the writing of GURPS Dinosaurs, it was perceived as a generic Allosaurus-like theropod with a sail on its back. In the mid to late 90’s, this perception would be altered by a more accurate understanding of spinosaurid skulls, reshaping Spinosaurus‘ face from that of a generic theropod to a far longer, almost crocodile-like skull; this is the Spinosaurus that would appear before cinema-goers in 2001’s Jurassic Park III. Finally (for now), the body of Spinosaurus would also receive greater understanding courtesy of new specimens studied by Nizar Ibrahim and colleagues in 2014. What came forth was a truly strange dinosaur.

Unlike the normal long-legged gaits of more typical spinosaurids such as Baronyx and Suchomimus, Spinosaurus had surprisingly short legs and splayed feet that were likely webbed. This, combined with an almost rectangular sail and a generally slim build, paints the image of a truly strange 50′ long amphibious dinosaur that would have been more than a match for any of the large fish swimming in the waters of coastal Egypt, using the huge meat-hook claws on its hands and numerous conical teeth to restrain prey. In spite of its strange anatomy, studies by Donald M. Henderson suggest that Spinosaurus still had a center of gravity around its hips, indicating a bipedal mode of locomotion.

Reigning at the end of the non-avian dinosaurs’ time on this planet (around 68 to 66 MYA), the 40′ long tyrannosaurine Tyrannosaurus was found across much of western North America, from southern Canada all the way down to Texas and possibly Mexico. Its most famous residence was the intensely studied Hell Creek Formation, lying on the 66 MYA tip of the age of dinosaurs, where it shared the landscape with other famous dinosaurs such as Ankylosaurus, Dakotaraptor, Edmontosaurus annectens (formerly filed variously under the defunct genera Anatosaurus, Anatotitan, and Trachodon), Pachycephalosaurus, and Triceratops.

Tyrannosaurus was an animal built for power; its skull, in addition to being a fair bit wider than the snout at the back to allow its large forward-facing eyes unimpeded binocular vision, was robust to both deliver and resist the impact of immense bite force. Unlike the thin blade-like teeth of earlier theropods, its thick teeth were like serrated spikes, designed to puncture rather than slash. These teeth would have been primarily deployed against juvenile hadrosaurs – multiple juvenile Edmontosaurus annectens have Tyrannosaurus-style bite wounds, including some that healed after a lucky escape – as well as against other Tyrannosaurus in face-biting conflict resolution. Its legs were built for a sort of fast walk rather than a run, giving it great stride length and energy conservation, and the famed tiny arms and two-fingered hands were backed up by powerful muscles in spite of their short length.

The statistics can also be used for the similar tyrannosaurids Tarbosaurus (Mongolia, around 70 MYA) and Zhuchengtyrannus (China, around 74 MYA).

At 18′ in length and tall enough to look a human in the eye, Utahraptor was one of the largest dromaeosaurids. It lived in the western United States on the threshold between the Barremian and Aptian ages (around 125 to 124 MYA), hunting the same territories that would yield Deinonychus later in the Aptian. Utahraptor was originally interpreted as being much like an upscaled Deinonychus, in fact, but more recent and complete specimens have shown that it was an even stockier theropod with a relatively shorter tail, robust back muscles, and strong legs built for power over speed. Assuming it also used the RPR method of hunting, it would have been able to clench onto larger and stronger prey than its later relative. The largest point of data for Utahraptor at the current time is a large sandstone slab containing seven individuals of varying ages, all of which died alongside an iguanodontid of indeterminate genus in a quicksand trap. As with Deinonychus, this has been alternatively interpreted as either evidence of pack hunting or a continued ‘pile up’ within the death trap.

Variant, Dakotaraptor [+5 Points]: Part of the fauna of the end-Cretaceous Hell Creek assemblage, Dakotaraptor was comparable in size to Utahraptor, but followed a more traditional dromaeosaurid body plan. Remove Basic Move penalty [5], decrease ST bonus to +10 [-12], and increase DX bonus to +3 [12]. Average Dakotaraptors have Running 12 added to their skill list.

Velociraptor is arguably the most famous of all dromaeosaurids, albeit under a stolen face; much has been written about the usage of Deinonychus as the basis for the ‘Velociraptor‘ of Jurassic Park, and its questionable accuracy even then, and it is ultimately irrelevant to this post. The true Velociraptor was around 6′ in length and knee-high to a human, and multiple species in the genus roamed the deserts and scrub of Cretaceus Mongolia from around 85 to 70 MYA. Its long, slender head was probably second to its killing claws in dispatching prey, and the scleral rings around the eye socket have been extrapolated to be comparable to those of modern nocturnal species, meaning Velociraptor most likely hunted at dusk or during the night.

Variant, Dromaeosaurus [-3 Points]: The namesake of the dromaeosaurids, Dromaeosaurus was around the same general size as Velociraptor but with a slightly bulkier frame and boxier snout. It lived in Canada from around 76 to 74 MYA. Increase ST penalty to -3 [10], reduce DX bonus to +3 [-12], and remove Sure-Footed [-1].